I'd predicate the answer to this question on a much more materialistic basis than the author : it's weird to sell software because it's doesn't really exist. I mean, it's barely tangible. You can copy it indefinitely. It doesn't exist physically. It's much more natural really to buy, say, a painting or a house. You can hang it, see it, use it. You have exactly one house, exactly one of this painting. Software, compar…
How is that different from music, TV, movies. Is entertainment a real thing? What about education, is that a tangible commodity? That's the kind of thinking that lead Marx to his theory of value, and his belief in the parasitic nature of all economic activities except for making physical things.
Where I live education is mostly free anyway, and artists are heavily subsidized by the state. Greatest artists of the past had benevolent patrons, for a reason.
Actually I'm fairly familiar with Marx, not in a classic leftist way though. Not sure he could have predicted the whole information industry thing but I've always seen the whole GNU/Linx/free software paradigm as the only True Communism™ that exists, and maybe that's why paying for software is a difficult thing.